Method of and apparatus for producing cutting and abrading articles



2 Sheets-Sheet 1 INVENTOYR ATTORNEY March 14, 1944. R TAYLOR METHOD OF. AND APPARATUS FOR PRODUCING CUTTING vAND ABRADINGARTICLES Filed Au 4, 1942 March 14, 1944. R. H. TAYLOR METHOD OF AND APPARATUS FOR PRODUCING CUTTING AND ABRADING ARTICLES Filed Aug. 4, 1942 2 Sheets-Sheet 2 B Hug/521322577 &

ATTORNEY Patented Mar. 14, 1944 METHOD OF AND APPARATUS FOR PRO- nucmc CUTTING AND ABRADING narr- CLES Rutherford B. Taylor, Miilburn, N. 1., assignor to J. K. Smit & Sons, Ina, New York, N. Y., a corporation of New York Application August 4, 1942, Serial No. 453,546

14 Claims. ,(Ql. 22-122) This invention relates to an impr ved method of producing articles comprising a etal matrix with cutting and abrading particles embedded therein. My invention therefore is useful in a great variety of industries. However, for purposes of this application I have elected to illustrate the same in connection with the making of diamond tools such as rotary drill bits.

In the setting of industrial diamonds in the making of diamond tools, several methods have been employed which while used quite extensively are not entirely satisfactory and require skilled labor. One prior method of setting diamonds in diamond tools is to form depressions in the face of the tool blank, place a diamond in each depression and then with punches and mauls facets are formed about the diamonds to hold them in place. This operation is slow and requires skilled and experienced operators.

Another method heretofore employed involves arranging the diamonds in a mold and while retaining them in position with a plastic, heat and pressure is applied to a mass of powdered metal confined within the mold. This method while workable fails to produce a tool in which the diamonds'will be adequately retained in place when the tool is put in service, so that the loss of diamonds is objectionably high.

A still further method which has been employed is to cast a matrix about the diamonds, by arranging the diamonds in the bottom of-a mold and pouring molten metal into the mold upon the diamonds. Difflculties have been experienced with this method, however, in holding the diamonds in their proper places during the process of pouring the molten metal, due to floating of the diamonds.

The present method and apparatus eliminates the drawbacks and difficulties of the methods above referred to in a very simple, inexpensive and eflicient fashion.

Briefly the present invention contemplates introducing molten metal below the diamonds, instead of upon them, and forcing this molten metal upwardly about the diamonds. In this way I at once eliminate the floating problem, the skill that is required in the hand setting method above referred to is not required, and I obtain excellent retention of the diamonds in the cast metal matrix as distinguished from the relatively poor results obtained in the powdered metal process, wherein, as above explained, the diamond loss is objectionably high owing to poor retention of the diamonds against dislodgment.

In the accompanying drawings I have illus trated one embodiment ,of my invention in the form of a suitable equipment for the casting of diamond core bits. As above pointed out, however, this apparatus is purely illustrative and not deiinitive inasmuch as obviously changes may be made therein within the purview of my invention.

It is to be understood, also, that'the showing of a. diamond core bit is for purposes of illustration and description only, inasmuch as my invention obviously may be employed in the manufacture of articles other than diamond core bits.

Fig. 1 is an elevational view of an apparatus suitable for the practice of my invention; and

Fig. 2 is a sectional elevational view of the mold portion of the apparatus of Fig. 1.

Referring .to the drawings in detail: 2 designates the base of my improved. apparatus. Mounted upon this base is a cupped member or block 3 into which is threaded a cylindrical shell 4 provided exteriorly with electric winding 6. The shell 4 contains a carbon tube or cylinder 8 provided with piston ill, to the upper end of which plunger 12 is secured. As will be brought out hereinafter, the winding 6 is for heating the structure to prevent too sudden cooling of the molten metal during the casting operation.

Mounted upon the top of the structure so far described is a split strap or ring H which receives the preformed threaded hollow shank l6 of the bit, the matrix to be cast being united to this shank in the casting operation.

The head 18 of the shank it extends upwardly into a mold cavity 20 formed in a block 22 which sits upon the split strap or ring l4 above referred to.

Resting in an annular depression in the top of the mold block 22 is a mold cover plate or diecover plate 24. Thisoover plate on itslower face is shaped so as to be complementary to the shape desired of the working end of the finished tool. Inasmuch as I have illustrated an apparatus for casting core bits, and inasmuch as the working end or nose of the bit is to be convex, the un derside of the plate 24 is concaved, as shown at 26, and this portion of the plate is drilled to provide a series of diamond-receivingholes 28. The pattern of these holes conforms of course to the desired disposition or arrangement of the diamonds in the finished tool. As above mentioned, the plate 24 is cup shaped, which provides a cavity or chamber 30 at the upper side of the plate.

Extending through the center of the cover plate 24 is a tubular member 32. The lower end its upper portion is of steel andextends through the cover plate 34 of the member 24.

The member 32 functions asa pouring tube for introducing molten metal into the mold cavity plate 34 so as to clamp all parts in position.

Communicating with the lower end of the cylinder 8 is compressed air line 38. This line is equipped with valve 40 which is adapted to be opened and closed by' foot pedal 42.

Communicating with the chamber 30 at the top of the mold is suction line H.

In the casting of a tool I proceed as follows: With 'the mold cover plate 24 out of the mold and upside down as compared with the showing in .the drawings,'I dispose the diamonds which are to constitute the cutting elements of the tool in the openings or orifices 2B of the plate. This assembly may then be sprayed with any suitable adhesive, such, for example, as collodion. After the pouring tube 32 has been inserted in the plate and the tool shank l8 has been placed in position, the die plate with the diamonds adhering thereto is inverted and placed in position on the mold body member 22. The cap or cover 34 may now be placed in position and the arm of the shank being provided with ports 48 into which the molten metal is forced during casting.

In the casting operation some of the molten metal is forced past the diamonds through the orifices 28. This produces fine filaments of metal projecting from the working and of the tool. These are easily broken off and the tool sandblasted or otherwise treated to give it the desired finish.

As stated near the outset of this specification, an equipment for producingcore bits has been illustrated for purposes of description only, it being very obvious that changes may be made therein for producing the same or other tools without departing from the spirit and scope of my invention.

What I claim is:

1. The method of forming a metal matrix with cutting and abrading particles embedded therein, which method comprises confining the particles in a mold and then introducing molten metal into the mold from beneath the particles.

2. The method of forming a metal matrix having cutting and abrading particles embedded therein, which method comprises confining the particles in the upper part of a mold, introducing 38 swung into place and tightened down so that the parts are all now in position fo casting.

With the circuit to the winding l2 closed the equipment is allowed to stand until it has heated up to say four or five hundred degrees Fahrenheit or to whatever other temperature may be found desirable. The purpose of this heating is to prevent too sudden cooling of the molten metal when it is poured into'the mold.

The suction line 44 is now operated to exhaust all cavities of the mold so far as possible thereby to free the same of gases and promote the production of a casting free of blowholes. is preferably maintained throughout the actual casting operation so as to insure the removal of such gases as are evolved during the casting operation. The molten metal may now be poured through the pouring tube 32, entering the mold as above explained beneath the diamonds and almost simultaneously therewith the pedal 42 is operated to open the valve In and to admit compressed air to the cylinder 4 beneath the piston III. This quickly forces the plunger l2 upwardly in the cylinder -8 and hollow tool shank l6 to ,cause the molten metal to flow into intimate contact with and about the diamonds at the orifices 28 and about the end of the tool shank, to produce Suction a matrix attached to the shank with diamonds embedded in the surface thereof.

It will be appreciated from the foregoing that there is no floating" problem to contend with in practicing my invention, inasmuch as the dia monds are at the top of the mold andthe molten metal is admitted beneath them and then forced upwardly by the plunger '1 2. I find, furthermore,

molten metal into the mold from beneath the particles and while the metal is still in molten condition applying upward pressure to the same.

3. The method of making diamond tools comprising a metal matrix having diamonds embedded therein, which method comprises temporarily anchoring the diamonds in a mold and then introducing molten metal into the mold from beneath the diamonds while preventing upward movement of the diamonds.

4. The method of making cutting and abrading tools composed of a metal matrix having cutting and abrading particles embedded therein,

which method comprises introducing molten metal into the lower part of a, covered mold with the cutting and abrading particles held against upward movement by the mold cover. v

5. The method of making cutting and abrading tools composed of a metal matrix having cutting and abrading particles embedded therein, which method comprises securing the cutting and abrading particles in the form of an annulus to the underside of the cover plate of a mold, pouring molten metal into the mold through the cover plate within the inner periphery of the annulus and then forcing the molten metal upwardly of the mold and laterally into contact with the cut- .ting and abrading particles.

6. The method of makingcutting and abrading tools composed of a metal matrix having cutting and abrading particles embedded therein, which method comprises disposing the preformed shank of the tool in the lower part of a mold, disposing the cutting and abrading particles in the upper part of the, mold above and spaced from th tool shank, and while retaining the shank and particles against relative movement introducing molten metal into the space between the two for flow about the end of the shank and about the cutting and abrading particles whereby a matrix is formed in which the end of the tool shank and the cutting and abrading particles are embedded.

'7. The method of making cutting and abrading tools composed of a metal matrix with cutting and abrading particles embedded therein, which method comprises temporarily adhesively securmolten metal into the mold beneath the cutting and abrading particles and applying pressure'to with the cutting and abrading particles.

8. An apparatus for molding articles composed of a metal matrix having cutting and abrading particles embedded therein, said apparatus comprising in combination a closed mold having provision for introducing the molten metal, which is to constitute the matrix, into the mold beneath the cutting and abrading particles.

. 9. 'An apparatus for molding articles composed of a metal matrix having cutting and abrading particles embedded therein, said apparatus comprising in combination a mold, a plate at the top of the mold cavity to'the underside of which the cutting and abrading particles are adapted to be held, means for admittingthe metal of the matrix in molten condition to the mold cavity beneath the cutting and abrading particles, and a plunger for exerting upward pressure on the molten mass.

10. An apparatus for molding articles composed of a metal matrix having cutting and abrading particles embedded therein, said apparatus comprising in combination a mold, a plate across the top of the mold cavity to the underside of which cutting and abrasiv particles may be held temporarily, means for admitting the metal of the matrix while molten to the mold cavity beneath the cutting and abrading particles, and an air operated plunger for exerting upward pressure on the molten mass to cause the same to flow about and in contact with the cutting and abrasive particles. 7 i

11. An apparatus or molding articles comprising a metal matrix with embedded cutting and abrading particles, said apparatus comprising in combination a mold having a plate across the cause the molten metal to flow around and in contact with the cutting and abrading particles.

12. An apparatus for producing cutting and abrading tools comprising a metal matrix and embedded cutting and abrading particles, said apparatus comprising in combination a mold equipped with a perforated plate across the top oi the mold cavity to the underside of which plate the cutting and abrasive particles may b attached temporarily, the upper side of said plate being cupped, a cover plate for said cupped portion of the plate, a suction line in communication with the chamber thus formed at the upper side of said perforated plate, and a pouring tube adapted to admit the molten matrix metal to the mold cavity while the cavity is exhausted by said suction means.

13. An apparatus for producing cutting and abrading tools comprising a metal matrix molded to a preformed metal tool shank, the cutting and abrading particles of the tool being embedded in the said matrix, said apparatus comprising in combination a mold into the cavity of which the preformed tool shank is adapted to be projected, a plate across the top of the mold cavity, said plate being perforated and the cutting and abrading particles being adapted to be attached temporarily to the underside oi.- said plate at said perforations, a pouring tube leading into thev mold cavity between the tool shank and the said perforated plate so that the molten metal of the matrix may be introduced into the mold cavity an air operated plunger extending into the tool top of the mold cavity, to the underside of which i shank for exerting upward pressure on the molten metal to cause the same to flow about the cutting and abrading particles.

14. The method of making cutting and abrad ing tools composed of a matrix having cutting and abrading particles embedded therein, which method comprises pouring molten metal into a mould cavity beneath the cutting and abrading particles and while restraining the particles against upward movement and while the metal is still in a molten condition imposing upward pressure upon the -metal, this pressure being.

maintained until the metal has solidified. V RUTHERFORD H. TAYLOR. 

